Gyroscope position indicating device



Patented Dec. 19, 1950 TS TA. TE S T Fl CE GYROSCOPE'PO'SITION INDICATING DEVICE Alanrll/L MacGallum, Maywood, N..J., assignorl to -:Bendix Aviation Corporation, "Ieterboro, N .l J a corporation of Delaware 'Applicatiunseptember 16, 1946, Serial No. 697,203

'5 Claims.

"The present invention relates to indicating devices :generally and more particularly to a .flasher: or fblinker type .of 1 indicator where-by operation thereof. imparts to an operator valuable information of.a-con'dition-existingiat a point removed some distance :from' the operator.

With the .present -simpliiication of automatic steering systems "for mobile-craft such as aircraft, forsexample, the artificial horizon or gyro verticalatogether with its .pitchand bank signal takeeolis has :been .moved from the instrument panel-pr automatic: pilot panel and has been arranged, ttogether with. other controls, within a closedccompact-casing containing the thermionic amplifier of the system. :The difficulty with this arrangementphowever, is that inasmuch as the entire casing :is closed andremoved from the human pilot, it is impossible to know, with power applied-to the system, when the gyro has come upto speedand also whether. or not its spin axis is in .the required" substantially vertical position. This knowledge is :important because the automatic 'steeringsystem cannot safely take over control of the rudder,;aileron-and elevator craft surfaces -.until the .horizon gyro is up to speed with its :spin in a substantially vertical position.

The. present invention has forone of its objects, therefore, the provision .of a novel indicating mechanism whereby the human pi ot will be visually informedas to the condition of the artificial:.horizon gyro, locatedat a remote point, so thathe will refrain'from-engaging the automatic steering system until certain desired conditions are indicated by the mechanism to exist at the i gyro.

Another object of the present invention is to provide a novel flasher or blinker type of indicating mechanism.

.-A further object-is to-provide'a novel electrical remote indicator adapted for use wherever it is desiredto indicate atone point the existence of certain desired conditions at another and remote point.

Another object is to provide a, novel arrangement for indicating the position of a gyroscope located ata remote point Withoutany-mechanical connection-betweenthe gyro and the indicator.

A further object of the present invention is to provide a novel "flashei 'or blinlcer type of mechanism incorporated in an electric circuit having a firingtube-which is normally biased to cut-off but which is fired upon the occurrence of "a desired condition.

"The above and ether .objectsand advantages Lil of the invention will appear more fnllyhereinafter from a consideration of the detailed description whichiollows; taken together with the accompanying. drawing wherein one embodiment of the invention is 1 illustrated. It'is .to be expressly understood, howeventhat the drawing: is for the purpose of illustration and description only and is'not designe'das a definition of the limits of the invention.

In the 1 drawings, Figure :1 represents a wiring diagram of the novel indicating mechanism of the present invention in .its application to-an-artificialj horizon gyro or gyro verticalwandhigure 2 is: a Wiring diagram oiraa conventional bandpass filterfor use withthercircuitof-Figure 1 under certain conditions.

The novel indicating mechanism oiithepresent invention is shown in Figure lot the drawing as applied to a conventional artificial horizon gyroscope having either-an electrically or pneumatically driven rotor it provided with normally vertical spin axis defined'hy a 'trunnion I 'l which journals the rotor within-a suitable casing 12. The latter casing, :in turn, is ijournalled vfor oscil-ation about-a first I horizontal axis within a gimloal ringlt by way'of trunnionstdpthering, inturn, being journalledforoscillation about a secondhorizontalaxis perpendicular to thefirst axis of oscillationioyw-ay of trunnions [5 (one onl-y'being shown in Figure 1) within a closed casing l5 having aipartition wall ll-therein.

Iii-order to maintain. 'thegyro spin axis in a substantially vertical position, a conventional erection 'mechanism is 1 provided comprising a rotating carriage -l8.1oosely sleeved about the spinning "trunnion 1! and =driven-thereby at a greatly reduced speed through-a slip-drive connection 19, the carriagebeing provided with a regulating or escapementmechanism Ed, and a rolling mass or ball 2| being driven by thecarriage within a ball t/rack 22 formed on therotor casing. 31110813116 erection mechanism per se constitutes no 5 part 1 of the present invention, except-that itscarriageconstitutes asuppor-t for a reflector element to be hereinafter described, reference for a more detai ed description of the structure and operationpf such a'mechanism is made to US. Patent No. 2,159,118, issued May 23, 1939, to Robert Alkan.

It will be apparentthat upon the application of power to-the gyro there is no way of knowing when the gyro has=attained its required speed or whenthe spin axisthereof hasattained-a substantially-vertical position, th-isbeing therequired position before a system such as an automatic pilot can be connected to the craft control surfaces to assure proper control thereof. By the present invention a novel indicating mechanism is provided whereby the human pilot at a remote point from the blind gyro is informed as to the existence or non-existence of certain required conditions at the gyro.

To this end, carriage |8 of the erection mechanism supports thereon or has formed integrally therewith a reflector element such as a mirror 23 which is adapted for reflecting radiant energy from a suitable source such as a lamp 26, for example, mounted to the right of wall ll within casing is to a conventional phototube 25, having an anode '26 and a cathode 2?, also mounted to the right of wall ll within casing i6 and spaced somewhat from lamp 2d, a suitable window 28 being arranged in wall It between the mirror and the lamp and phototube. A lens 23a may be arranged between window 28 and reflector 23 to concentrate and cast a beam of light from the lamp on to the phototube. A shield 29 for the lamp may be provided to assure impingement on the cathode of the phototube of only those rays reflected by the mirror. So long as the gyro spin axis is in the substantially vertical position shown, for each rotation of carriage |3, mirror 23 will pass window 28 and at that moment reflect radiant energy from the lamp through lens 230. on to the cathode of the phototube to activate the latter. On the other hand, if the gyroscopic spin axis is in some position other than its substantially vertical position, mirror 23 rotating with carriage It will be displaced with respect to window 28 so that no energy will be reflected thereby to the cathode of the phototube.

The indicator per se is a blinker or flasher device in the form of a neon lamp 5| having two electrodes 3|] and 3|, the former connecting by way of a conductor 32 with the plate 33 of a conventional gas-filled tube 34 and the latter conheating by way of a conductor 35 with one end of an auto-transformer coil 36. Anode 26 of the phototube is connected by way of a conductor 31 with a substantially central point of transformer coil 36 while the cathode 38 of the tube connects by way of a conductor 39 with coil 36 in such a manner that cathode 38 is negative with respect to its related anode or plate 33. Cathode 27 of the phototube, on the other hand, connects by way of a conductor all with a grid 4| of the tube, and this grid as well as cathode 2i connects with the opposite end of transformer coil 36 by way of a conductor 12, resistor 43, adjustable contact Mi, resistor 45 and conductor 46, resistor 35 being tapped to conductor 39. The outermost ends of coil 35 are connected by way of leads 47 and 58 to a suitable source of alternating current (not shown).

The negative charge on grid 4| of the tube 36 is initially determined by adjustment of contact 44 relative to resistor 45, the adjustment being such as to bias the grid to cut-ofl, i. e., with nothing more on the grid the tube will be nonconducting.

When tube 34 is non-conducting current cannot flow at lamp 5|. Plate 33 of tube 34, however, will have a positive potential for each positive half cycle of A. C. current applied to coil 35 by lead i? and cathode 38 will have a negative potential. Since grid 4| is at its most negative point the tube will be incapable of firing. For the next half or negative cycle of A. C. current at coil 35, the plate becomes negative while the cathode and grid become positive but this is immaterial because the tube conducts only when the plate is positive.

When cathode 2! of the phototube is activated or sensitized by radiant energy reflected thereto, current flows from cathode 21 to the anode thereby developing a difierence in potential across resistor 43 and making grid 4| of the tube less negative so that tube 34 will fire each time that the plate is positive. As the tube fires, current is caused to flow in the plate circuit developing a difierence in potential across electrodes 35 and 3| whereupon current flows between the electrodes providing a flash at lamp 5| which is extinguished as plate 33 becomes negative and cathode 21 of the photo tube is de-activated.

It will now be apparent that for each revolution of carriage I8, assuming the gyro spin axis to have attained its substantially vertical position, mirror 23 will pass window 28 and, at that point, reflect radiant energy from source 24 to activate or sensitize cathode 21 of the photo tube whereby tube 34 fires producing a flash at lamp 5 I. Until neon lamp 5| begins flashing or blinking, the pilot will know that his gyro is still not in the position required before the automatic steering system can be engaged with the craft control surfaces. Moreover, since the speed of the gyro rotor bears a definite relation to the speed of the erection mechanism as pointed out in the aforementioned Alkan patent, the pilot, by counting the number of flashes provided by lamp 5| in one minute, will be able to determine the speed of the gyroscope as well as its position.

Reflector element or mirror 23 has been shown as carried by the carriage of the erection mechanism, however, it could be attached as well to rotor trunnion ii and be rotated thereby to provide the same information, when the spin axis is in its substantially vertical position, at lamp 5|. In this case, however, it would be necessary to incorporate the conventional band pass fllter 5% of Figure 2 within conductor 49, the filter being tuned to rotor frequency.

Assuming, for example, the rotor speed to be about 20,690 E. P. M., the frequency to be passed to grid 4! will be about 333 cycles per second. In order that the neon lamp 5| will not flash until the rotor has attained its speed, the band pass filter is made resonant to 333 cycles at which time maximum voltage will be available while other frequencies will be attenuated. The frequency of the flashes at lamp 5| with this arrangement will be high giving the eiiect of a continuous glow at the lamp.

Although but one embodiment of the invention has been illustrated and described, various changes and modifications in the form and relative arrangement of parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

I claim:

1. The combination with a three-degree-offreedom gyroscope having a rotor mounted for oscillation about two mutually perpendicular horizontal axes and provided with a spin axis which, when the rotor has been energized for a predetermined interval of time, is adapted for attaining a substantially vertical position but which, when the rotor is initially energized subsequent to a rest period, is at an initial position other than said substantially vertical position, together with means for erecting said spin axis into said substantially vertical position, of means for indicating at a point remote from said gyro when the gyro spin axis has been brought into said substantially vertical position by said erecting means, means comprising an electrical circuit incorporating said indicating means therein and operating the latter when the circuit is energized, and means movable with said rotor spin axis into said substantially vertical position from said initial position and rotatable about said spin axis for energizing said circuit when the spin axis has attained said substantially vertical position.

2. The combination with a three-degree-cffreedom gyroscope having a rotor mounted for oscillation about two mutually perpendicular horizontal axes and provided with a spin axis which, when the rotor has been energized for a predetermined interval of time, is adapted for attaining a substantially vertical position but which, when the rotor is initially energized subsequent to a rest period, is at an initial position other than said substantially vertical position, together with means for erecting said spin axis into said substantially vertical position, of means for indicating at a point remote from said gyro when the gyro spin axis has been brought into said substantially vertical position by said erecting means comprising a phototube for operating said indicating means when said phototube is activated, and means movable with said rotor spin axis into said substantially vertical position from said initial position and rotatable about said spin axis for activating said phototube when the spin axis has attained said substantially verhorizontal axes and provided with a spin axis which, when the rotor has been energized for a predetermined interval of time, is adapted for attaining a substantially vertical position but which, when the rotor is initially energized subsequent to a rest period, is at a position other than said substantially vertical position, together with means for erecting said spin axis into said substantially vertical position, of means for indicating when the gyro spin axis has been erected into said substantially vertical position by said erecting means comprising an electrical circuit and a phototube in said circuit for energizing said circuit when said phototube is activated, a source of radiant energy, and means movable with said rotor spin axis into said substantially vertical position and rotatable about said spin axis for intercepting said energy from said source and reflecting it to said phototube to activate the latter when the spin axis has attained said substantially vertical position.

4. The combination with a three-degree-offreedom gyroscope having a rotor mounted for oscillation about two mutually perpendicular horizontal axes and provided with a spin axis which, when the rotor has been energized for a predetermined interval of time, is adapted for angularly moving into a substantially vertical position but which, when the rotor is initially ener gized subsequent to a rest period, is at a position other than said substantially vertical position, together with a casing for said rotor and an erection mechanism on said casing for erecting said spin axis into said substantially vertical position, of means for remotely indicating when the gyro spin axis has been erected into said substantially vertical position by said erecting mechanism comprising an electrical circuit and a phototube in said circuit for energizing said circuit when said phototube is activated, a source of radiant energy, and a reflector surface carried by said rotor casing and angularly movable with said rotor spin axis into said substantially vertical position, said surface also being rotatable about said spin axis for intercepting said energy from said source and reflecting it to said phototube to activate the latter when the spin axis has attained said substantially vertical position.

5. The combination with a three-degree-offreedom gyroscope having a rotor provided with a spin axis which, when the rotor has been energized for a predetermined interval of time, is adapted for angularly moving into a substantially vertical position but which, when the rotor is initially energized subsequent to a rest period, is at a position other than said substantially vertical position, together with a casing for said rotor and an erection mechanism on said casing for erecting said spin axis into said substantially vertical position, of means for visually indicating at a remote point when the gyro spin axis has attained said substantially vertical osition comprising a neon lamp, means comprising a thermionic tube connected to said lamp for energizing the latter when said tube is energized, a source of radiant energy, means responsive to radiant energy for energizing said tube, and means angularly movable with said rotor into said substantially vertical position and rotatable about said spin axis for reflecting energy from said source to said radiant energy responsive means when the spin axis has attained said substantially vertical position.

ALAN M. MACCALLUM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,455,795 Logan May 22, 1923 1,746,562 Sounitza Feb. 11, 1930 1,957,236 Stewart May 1, 1934 2,317,632 Miller Apr. 2'7, 1943 2,365,601 iSipman Dec. 19, 1944 2,438,406 Konet Mar. 23, 1948 FOREIGN PATENTS Number Country Date 548,661 Great Britain Oct. 20, 1942 

